bug#62237: 28.1 or higher: 24-bit true color breaks colours in Emacsen built without X under GNU Screen

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: sdt@sebyte.me,  62237@debbugs.gnu.org
> Date: Fri, 17 Mar 2023 18:44:19 +0100
> 
>     Eli> Is this screen.FOO format documented somewhere in screen's
>     Eli> documentation?
> 
> Yes:
> 
>        When screen tries to figure out a terminal name for  itself,  it  first
>        looks  for an entry named "screen.<term>", where <term> is the contents
>        of your $TERM variable.  If no such entry exists, screen tries "screen"
>        (or  "screen-w"  if  the terminal is wide (132 cols or more)).  If even
>        this entry cannot be found, "vt100" is used as a substitute.
> 
>        The idea is that if you have a terminal which doesn't support an impor‐
>        tant  feature  (e.g.  delete  char or clear to EOS) you can build a new
>        termcap/terminfo entry for screen (named "screen.<dumbterm>") in  which
>        this  capability  has been disabled. If this entry is installed on your
>        machines you are able to do a rlogin and still keep the  correct  term‐
> -->    cap/terminfo  entry.  The terminal name is put in the $TERM variable of
>        all new windows.  Screen also sets the $TERMCAP variable reflecting the
>        capabilities of the virtual terminal emulated. Notice that, however, on
>        machines using the terminfo database this variable has no effect.  Fur‐
>        thermore, the variable $WINDOW is set to the window number of each win‐
>        dow.

This seems to tell how 'screen' figures out the terminal name, not how
it sets TERM.  I asked who and why sets TERM to screen.SOMETHING.